1. Field of the Invention
The present invention relates to novel histidine derivatives and to a process for their preparation. The invention also relates to cosmetic or dermatological compositions comprising these compounds. The invention also relates more particularly to the use of these compounds as anti-free-radical agents.
Solar radiation, heat, atmospheric pollution and, in particular, smoke and tobacco are known to lead to the formation of free radicals. They originate to a large extent from molecular oxygen.
Mention may be made of the following free radicals:
singlet oxygen, which is highly oxidizing, highly toxic and has a very short lifetime, produced by the excitation of molecular oxygen with photons of light; PA1 the superoxide anion radical, produced by the addition of an electron to oxygen and capable of giving rise to the production of highly reactive hydroxyl radicals; PA1 the hydroxyl radical, which is highly oxidizing and the most toxic to cells. PA1 R denotes a linear or branched, saturated or unsaturated alkyl radical containing from 6 to 22 carbon atoms, PA1 n is an integer from 1 to 16, PA1 Q.sup.+ represents H.sup.+ or an organic or inorganic cation, and the addition salts with an acid. PA1 (1) the glycerol derivatives of formula: EQU R.sup.10 O--[--C.sub.3 H.sub.5 --(OH)O--].sub.q --H PA1 --C.sub.3 H.sub.5 (OH)O-- is represented by the following structures, taken as a mixture or separately: ##STR6## PA1 q is an average statistical value between 2 and 6; PA1 R.sup.10 represents: PA1 (a) a linear or branched aliphatic chain containing from 12 to 18 carbon atoms; PA1 (b) a residue R.sup.11 CO, in which R.sup.11 is a linear or branched aliphatic C.sub.11 -C.sub.17 radical; PA1 (c) a residue R.sup.12 --[--OC.sub.2 H.sub.3 (R.sup.13)--]--, in which: PA1 (2) polyoxyethylenated fatty alcohols and polyoxyethylenated sterols, PA1 (3) optionally polyoxyethylenated polyesters; PA1 (4) natural or synthetic glycolipids; PA1 (5) oxyethylenated polyglyceryl stearate; PA1 (6) the glycerol derivatives described in PCT patent application No. 92/08685 and corresponding to formula (V): EQU HOCH.sub.2 --CH(OH)--CH.sub.2 --O--[--CH.sub.2 --CH(R.sup.14)--O--].sub.p --H (V) PA1 in which R.sup.14 represents a linear C.sub.14 to C.sub.18 alkyl radical or a group --CH.sub.2 Y in which Y is --OR.sup.15, R.sup.15 representing a linear C.sub.10 -C.sub.18, and preferably C.sub.16, alkyl radical and p represents an average statistical value greater than 1 and not more than 3, and, in addition, when R.sup.14 is --CH.sub.2 Y, p can also represent an integer equal to 2; and PA1 (7) fatty acid esters and ethers of .alpha.-butylglucoside which either can be mixtures of different fatty acid esters of .alpha.-butylglucoside and/or mixtures of different fatty acid ethers of .alpha.-butylglucoside, in which the various fatty chains contain a similar number of carbon atoms relative to each other (for example differing by 1 or 2), or can be mixtures of the same fatty acid mono-, di-, tri- or polyesters of .alpha.-butylglucoside and/or mixtures of the same fatty acid of mono-, di-, tri- or polyethers of an .alpha.-butylglucoside. PA1 (1) the following anionic amphiphilic lipids: PA1 natural phospholipids such as egg or soybean lecithin, sphingomyelin, phosphatidylserine, dipalmitoylphosphatidylcholine and hydrogenated lecithins, chemically or enzymatically modified phospholipids and synthetic phospholipids; PA1 the anionic compounds of formula (VI): ##STR8## PA1 R.sup.16 represents a C.sub.7 -C.sub.21 alkyl or alkenyl radical, PA1 R.sup.17 represents a saturated or unsaturated C.sub.7 -C.sub.31 hydrocarbon-based radical, PA1 M represents H, Na, K, NH.sub.4 or a substituted ammonium ion derived from an amine; PA1 anionic compounds such as phosphoric esters of a fatty alcohol, in particular dicetyl phosphate and dimyristyl phosphate in acidic form or in the form of alkaline salts, heptylnonylbenzenesulphonic acid, cholesteryl hydrogen sulphate or cholesteryl hydrogen phosphate, as well as the alkaline salts thereof, lysolecithins, alkyl sulphates such as sodium cetyl sulphate, gangliosides, monosodium and disodium acylglutamates, and in particular the monosodium and disodium salts of N-stearoylglutamic acid, the sodium salts of phosphatidic acid, phosphoaminolipids and natural phospholipids, PA1 (2) the following cationic amphiphilic lipids: PA1 cationic compounds of formula (VII): EQU (R.sup.18)(R.sup.19)N.sup.+ (R.sup.20)(R.sup.21)X.sup.- (VII) PA1 in which R.sup.18 and R.sup.9, which may be identical or different, represent C.sub.12 -C.sub.20 alkyl radicals and R.sup.20 and R.sup.21, which may be identical or different, represent C.sub.1 -C.sub.4 alkyl radicals, PA1 long-chain amines and the quaternary ammonium derivatives thereof, long-chain amino alcohol esters and the salts and quaternary ammonium derivatives thereof, PA1 polymerizable lipids, as described by Riingsdorf et al. in "Angewandte Chemie", vol. 27, No. 1, January 1988, pages 129-137. PA1 sterols and in particular phytosterols and cholesterol, PA1 long-chain alcohols and diols, PA1 long-chain amines and the quaternary ammonium derivatives thereof, can be added to the lipid phase.
The formation of these radical species leads in particular to oxidation of the lipids in the skin.
Live cells, in particular those in the skin, the scalp and certain mucous membranes, are particularly sensitive to these free radicals, which is reflected in accelerated ageing of the skin, with a complexion lacking radiance and early formation of wrinkles and fine lines, and also by a reduction in the vigour and a dull appearance of the hair.
It is thus seen that it is particularly important to protect the skin, the hair and the mucous membranes against these free radicals.
2. Description of the Related Art
It is known that certain antioxidants are capable of inhibiting the formation of free radicals.
Thus, carnosine, or N-.beta.-alanyl-L-histidine, which is a natural dipeptide found in the muscles of many vertebrates, is known for its anti-free-radical activity, in particular its activity against singlet oxygen (E. Decker and H. Faraji, JAOCS, vol. 67, No. 10, 650-652, 1990). Its use as an antioxidant or as anti-free-radical agent in cosmetics is also known from patent application WO-A-92/09298. However, when in contact with the skin, carnosine displays degradation problems caused by the enzymes present in the skin and in particular proteases, which leads to a substantial loss of its activity.
Carnosine derivatives are also known, such as, for example, the N-acyl carnosine derivatives described in patent FR-C-2,496,660. Products with antioxidant activity, obtained by coupling fatty acids and carnosine and used in cosmetic preparations, have been described in patent application FR-A-2,668,365. However, such carnosine derivatives also have the same problem of instability in the presence of the enzymes present in the skin.